Towable tent campers and pop-up trailers having collapsible roofs are generally known in the art. Prior art mechanisms used for raising and lowering collapsible tops on such structures are generally balky, hard to operate and maintain, and prone to failure. For example, many lifting mechanisms rely on cranks and cables that are exposed to the elements, can accumulate dirt and debris, and can bind, slip and stretch. Mechanisms which are based upon gear driven assemblies are significantly heavier and more expensive to produce.
The following U.S. Patents exemplify known lifting mechanisms: U.S. Pat. No. 6,206,456 to Steury, U.S. Pat. No. 5,865,499 to Keyser, U.S. Pat. No. 5,769,485 to Bontrager et al., U.S. Pat. No. 5,704,677 to Steury et al., U.S. Pat. No. 4,981,319 to Gerzeny et al., U.S. Pat. No. 4,362,258 to French, U.S. Pat. No. 4,317,590 to Young, U.S. Pat. No. 4,201,413 to Rowe, U.S. Pat. No. 4,171,843 to Steury, U.S. Pat. No. 3,981,529 to Bontrager, U.S. Pat. No. 3,924,889 to Gogush, U.S. Pat. No. 3,519,306 to Young, and U.S. Pat. Nos. 6,494,524 and 6,443,516 to Lambright.
The present invention provides extendable and retractable support systems that include telescopic assemblies which can be used to raise and lower various structures, including covers or tops of mobile and immobile dwellings.